Traditional sputtering apparatus include structure for either directly cooling the target or cathode, or cooling the cathode by attaching it to a cooled carrier plate. The cathode and carrier plate are joined together so that heat may be transmitted from the cathode to the carrier plate, in which case these components are either screwed, clamped, or welded together. In one known device, contact between the carrier plate and the cathode is achieved by providing the carrier plate as an elastic member that is pressed into contact with the cathode by the pressure of a coolant flowing through the plate. In other known devices, the cathode and carrier plate are tightly joined to one another by soldering or welding, and the coolant channel is formed with a thin wall at the cathode side, which may be pressed into contact with the cathode surface by coolant pressure.
German Patent No. 24 17 288 discloses a cathode sputtering apparatus having a planar cathode surface facing toward a substrate to be sputtered. The substrate is disposed close to the discharge region of the cathode, and can be moved in a plane parallel to the cathode surface. For this purpose, a magnet assembly generating a magnetic field is arranged at a side of the cathode facing away from the planar sputtering surface. A cooling plate penetrated by coolant channels is mounted so as to press firmly against a very rigid carrier plate. The carrier plate is in turn tightly screwed to the cathode. The coolant channels in the cooling plate are provided as grooves that are incised into the cooling plate at a side facing toward the cathode. The grooves are covered by a second carrier plate.
A particular disadvantage of the above described apparatus is that the cooling channels are frequently inadequately sealed. Another disadvantage is inadequate contact between the carrier plate and the cathode, due to the fact that the cathode is not metallically bonded to the carrier plate.